The present invention relates generally to antennas of electromagnetic radiation and more particularly to a multi-element broadside vertical array.
In military applications there exists a need for a high performance, light weight portable antenna which provides unidirectional radiation and reception of high frequency radio waves at low take off angles above the horizon in a compact configuration and which is particularly adapted for field use and can operate to provide communications in the HF or high frequency band (2 MHz-30 MHz) of the electromagnetic spectrum over medium range and long range ionospheric circuits.
One known type of radio antenna comprises what is referred to as the broadside vertical array and consists of a multi-element array configured of horizontal half wavelength conductors and vertical quarter wavelength conductors typically configured in what is referred to as either a half square array consisting of a single horizontal half wavelength conductor element whose ends extend into or are connected to a pair of vertical quarter wavelength conductor elements with a feed point being located at the bottom of one of the quarter wavelength conductors, or a double half square array also known as a "bobtail" array consisting of a pair of horizontal half wavelength conductor elements mutually connected together at one end by a vertical quarter wavelength conductor element and which includes a feed point at the bottom thereof and two outer vertical quarter wavelength conductor elements which are extensions of or are attached to the outer ends of the two half wavelength conductor elements. Such apparatus, moreover, has been shown and disclosed in a publication entitled, "The Half Square Antenna", which was published in the March, 1974 issue of QST of the American Radio Relay League by B. Vester at pp. 11-14.
Accordingly, it is an object of the present invention to provide improvement in high frequency communications antennas.
It is another object of the invention to provide an improvement in high frequency multi-element broadside vertical array antennas.
Still another object of the invention is to provide a high frequency antenna array which exhibits high front-to-back ratio, increased directivity gain, and one which provides a low angle of radiation in a single direction.
And yet another object of the invention is to provide a light weight portable antenna array which eliminates the requirement for an elaborate ground system or an impedance matching network.